There is quite difference between the debenture holder and equity holder
Refer section 88 for maintenance of register
Refer memorandum and article of the Company at the initial stage company formed either limited by share or guarantee
Most of the situation members are the primary holder of Company in terms of voting process etc. While debenture holders have only the specific rights over Interest payment etc. We can not allow them to participate as allow to members of the Company. Even company has no authority to treat both the holder of security i.e debenture and equity at same platform.
There are various situation whether it is appointment of Directors, Auditors or removal of it. Passing the special or ordinary resolution or entitle to share the profit by way of dividend . participate in further issuance of securities.